This invention relates to a method of incorporating three-phase motors and associated controls into a vehicle.
Vehicles have been historically equipped with a 12-volt power supply providing direct current. Vehicles have more and more electrical components, and are typically equipped with several motors for powering various accessories. As an example, the windows, the locks, the seats, moon roofs/sun roofs, etc., are all powered by separate motors. Historically, these motors have utilized direct current. In the near future, it is expected that the power supply on vehicles will be increased to 42 volts direct current.
There are motors which are less expensive and smaller than the typical direct current motor. One type of inexpensive and small motor is powered by three-phase alternating current. However, the use of three-phase motors has not been practical in the vehicle environment, since a three-phase power supply has not been practically available in the vehicle. Moreover, three-phase motors typically require associated controls, that would be relatively expensive. Thus, although there would be benefits to utilizing three-phase motors in the vehicle environment, this has not been practically realized.
In a disclosed embodiment of this invention, the use of three-phase motors is made more practical in the vehicle environment. In one feature of this invention, a single controller is utilized to control the supply of three-phase power to a number of three-phase motors. Essentially, a single controller, which may be the central controller for the entire vehicle, is operable to control switching elements associated with each of the motors. The controller controls the switching element to enable or prevent the flow of three-phase power to the individual motors.
In another aspect of this invention, pseudothree-phase power is supplied from a DC source. The DC current is associated with a xe2x80x9cchoppingxe2x80x9d element that chops the direct current into a series of pulses. The pulses are sent to a power shift register which translates the pulses into power pulses, and shifts the phase among sequential pulses to provide pseudothree-phase power to a motor.
This aspect can be combined with a common controller such that three-phase power is supplied to a plurality of motors, and a single controller is operable to achieve the flow of the current to the individual motors. In further aspects of this invention, the shift circuit can output unipolar or di-polar signals.
Further, the power converter to convert the voltage signals into power may be separate from the shift register.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.